Textron Cessna C172S PIM, Pilot Operating Handbook

Page: 110 / 322

SECTION 3 CESSNA
EMERGENCY PROCEDURES MODEL 172S NAV III
GFC 700 AFCS
U.S.
STATIC SOURCE BLOCKED
If erroneous readings of the static source instruments (airspeed,
altimeter and vertical speed) are suspected, the alternate static source
air valve (ALT STATIC AIR) should be pulled ON, thereby supplying
static pressure to these instruments from the cabin.
When the ALT STATIC AIR valve is ON, the maximum airspeed
variation from normal static source operation is 11 knots and the
maximum altimeter variation is 50 feet with all windows closed. Refer to
Section 5, Figure 5-1 (Sheet 2), Airspeed Calibration - Alternate Static
Source correction tables for additional details.
SPINS
Should an inadvertent spin occur, the following recovery procedure
should be used:
1. RETARD THROTTLE TO IDLE POSITION.
2. PLACE AILERONS IN NEUTRAL POSITION.
3. APPLY AND HOLD FULL RUDDER OPPOSITE TO THE
DIRECTION OF ROTATION.
4. JUST AFTER THE RUDDER REACHES THE STOP, MOVE
THE CONTROL WHEEL BRISKLY FORWARD FAR ENOUGH
TO BREAK THE STALL. Full down elevator may be required at
aft center of gravity loadings to assure optimum recoveries.
5. HOLD THESE CONTROL INPUTS UNTIL ROTATION STOPS.
Premature relaxation of the control inputs may extend the
recovery.
6. AS ROTATION STOPS, NEUTRALIZE RUDDER, AND MAKE A
SMOOTH RECOVERY FROM THE RESULTING DIVE.
NOTE
If the rate of the spin makes determining the direction of
rotation difficult, the magenta turn rate indicator at the top of
the HSI compass card will show the rate and direction of
the turn. The HSI compass card will rotate in the opposite
direction. Hold opposite rudder to the turn vector direction.
For additional information on spins and spin recovery, see the
discussion under SPINS in Normal Procedures, Section 4.
172SPHBUS-00
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